Genetic distance and pollinator sharing shape divergence in floral volatiles in closely related dioecious Ficus species
Xiaoxia Deng, Shuai Liao, Yao Ning, Changqiu Liu, Hui Yu, Finn KjellbergAbstract
Premise
Floral scent is central to host recognition in the fig–fig wasp mutualism, yet how scent divergence relates to pollinator sharing among closely related dioecious Ficus species remains unclear.
Methods
We analyzed volatile organic compounds (VOCs) from four pairs of closely related Ficus species that have different levels of pollinator sharing (complete, partial, or none). Floral scent profiles were compared using multivariate analyses, and their relationship with genetic distance was evaluated using a Mantel test.
Results
Floral scent profiles differed among species and were shaped by both genetic relatedness and pollinator sharing. Nonmetric multidimensional scaling (NMDS) ordination revealed clear clustering of species based on scent composition, and a PERMANOVA revealed significant interspecific differences, except between F. auriculata and F. oligodon , which share pollinators and have similar VOC profiles. In general, species pairs that share pollinators had greater similarity in scent composition than those that did not, although this pattern was not universal. Floral scent similarity declined with increasing genetic distance (Mantel test: r = −0.39, P = 0.041), indicating that closely related species tend to have more similar scent profiles.
Conclusions
Floral scent similarity is partly associated with pollinator sharing in closely related Ficus species, but this relationship is not consistent and likely depends on additional factors, including genetic divergence and ecological context. Overall, floral scent variation reflects the combined influence of evolutionary history and ecological processes. Broader taxonomic sampling and functional analyses of pollinator responses are needed to further clarify these relationships.